ocxl: Expose the thread_id needed for wait on POWER9

In order to successfully issue as_notify, an AFU needs to know the TID
to notify, which in turn means that this information should be
available in userspace so it can be communicated to the AFU.

Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
Acked-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/drivers/misc/ocxl/context.c b/drivers/misc/ocxl/context.c
index 909e8807824a9c48bb2ef8b64705012f13e63e6d..95f74623113e2c2063e523dcf0809a51041f3ced 100644 (file)
--- a/drivers/misc/ocxl/context.c
+++ b/drivers/misc/ocxl/context.c
@@ -34,6 +34,8 @@ int ocxl_context_init(struct ocxl_context *ctx, struct ocxl_afu *afu,
        mutex_init(&ctx->xsl_error_lock);
        mutex_init(&ctx->irq_lock);
        idr_init(&ctx->irq_idr);
+       ctx->tidr = 0;
+
        /*
         * Keep a reference on the AFU to make sure it's valid for the
         * duration of the life of the context
@@ -65,6 +67,7 @@ int ocxl_context_attach(struct ocxl_context *ctx, u64 amr)
 {
        int rc;
 
+       // Locks both status & tidr
        mutex_lock(&ctx->status_mutex);
        if (ctx->status != OPENED) {
                rc = -EIO;
@@ -72,7 +75,7 @@ int ocxl_context_attach(struct ocxl_context *ctx, u64 amr)
        }
 
        rc = ocxl_link_add_pe(ctx->afu->fn->link, ctx->pasid,
-                       current->mm->context.id, 0, amr, current->mm,
+                       current->mm->context.id, ctx->tidr, amr, current->mm,
                        xsl_fault_error, ctx);
        if (rc)
                goto out;

diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c
index 038509e5d031f44e99fee275c59b7b08421c9f29..eb409a469f21723a8d3d7c436dfa013c92dfe7ce 100644 (file)
--- a/drivers/misc/ocxl/file.c
+++ b/drivers/misc/ocxl/file.c
@@ -5,6 +5,8 @@
 #include <linux/sched/signal.h>
 #include <linux/uaccess.h>
 #include <uapi/misc/ocxl.h>
+#include <asm/reg.h>
+#include <asm/switch_to.h>
 #include "ocxl_internal.h"
 
 
@@ -123,11 +125,55 @@ static long afu_ioctl_get_metadata(struct ocxl_context *ctx,
        return 0;
 }
 
+#ifdef CONFIG_PPC64
+static long afu_ioctl_enable_p9_wait(struct ocxl_context *ctx,
+               struct ocxl_ioctl_p9_wait __user *uarg)
+{
+       struct ocxl_ioctl_p9_wait arg;
+
+       memset(&arg, 0, sizeof(arg));
+
+       if (cpu_has_feature(CPU_FTR_P9_TIDR)) {
+               enum ocxl_context_status status;
+
+               // Locks both status & tidr
+               mutex_lock(&ctx->status_mutex);
+               if (!ctx->tidr) {
+                       if (set_thread_tidr(current))
+                               return -ENOENT;
+
+                       ctx->tidr = current->thread.tidr;
+               }
+
+               status = ctx->status;
+               mutex_unlock(&ctx->status_mutex);
+
+               if (status == ATTACHED) {
+                       int rc;
+                       struct link *link = ctx->afu->fn->link;
+
+                       rc = ocxl_link_update_pe(link, ctx->pasid, ctx->tidr);
+                       if (rc)
+                               return rc;
+               }
+
+               arg.thread_id = ctx->tidr;
+       } else
+               return -ENOENT;
+
+       if (copy_to_user(uarg, &arg, sizeof(arg)))
+               return -EFAULT;
+
+       return 0;
+}
+#endif
+
 #define CMD_STR(x) (x == OCXL_IOCTL_ATTACH ? "ATTACH" :                        \
                        x == OCXL_IOCTL_IRQ_ALLOC ? "IRQ_ALLOC" :       \
                        x == OCXL_IOCTL_IRQ_FREE ? "IRQ_FREE" :         \
                        x == OCXL_IOCTL_IRQ_SET_FD ? "IRQ_SET_FD" :     \
                        x == OCXL_IOCTL_GET_METADATA ? "GET_METADATA" : \
+                       x == OCXL_IOCTL_ENABLE_P9_WAIT ? "ENABLE_P9_WAIT" :     \
                        "UNKNOWN")
 
 static long afu_ioctl(struct file *file, unsigned int cmd,
@@ -186,6 +232,13 @@ static long afu_ioctl(struct file *file, unsigned int cmd,
                                (struct ocxl_ioctl_metadata __user *) args);
                break;
 
+#ifdef CONFIG_PPC64
+       case OCXL_IOCTL_ENABLE_P9_WAIT:
+               rc = afu_ioctl_enable_p9_wait(ctx,
+                               (struct ocxl_ioctl_p9_wait __user *) args);
+               break;
+#endif
+
        default:
                rc = -EINVAL;
        }

diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c
index 656e8610eec269ac7c976016b24a011089dce91a..88876ae8f33004b4dce970e31fce773958d48b25 100644 (file)
--- a/drivers/misc/ocxl/link.c
+++ b/drivers/misc/ocxl/link.c
@@ -544,6 +544,42 @@ unlock:
 }
 EXPORT_SYMBOL_GPL(ocxl_link_add_pe);
 
+int ocxl_link_update_pe(void *link_handle, int pasid, __u16 tid)
+{
+       struct link *link = (struct link *) link_handle;
+       struct spa *spa = link->spa;
+       struct ocxl_process_element *pe;
+       int pe_handle, rc;
+
+       if (pasid > SPA_PASID_MAX)
+               return -EINVAL;
+
+       pe_handle = pasid & SPA_PE_MASK;
+       pe = spa->spa_mem + pe_handle;
+
+       mutex_lock(&spa->spa_lock);
+
+       pe->tid = tid;
+
+       /*
+        * The barrier makes sure the PE is updated
+        * before we clear the NPU context cache below, so that the
+        * old PE cannot be reloaded erroneously.
+        */
+       mb();
+
+       /*
+        * hook to platform code
+        * On powerpc, the entry needs to be cleared from the context
+        * cache of the NPU.
+        */
+       rc = pnv_ocxl_spa_remove_pe_from_cache(link->platform_data, pe_handle);
+       WARN_ON(rc);
+
+       mutex_unlock(&spa->spa_lock);
+       return rc;
+}
+
 int ocxl_link_remove_pe(void *link_handle, int pasid)
 {
        struct link *link = (struct link *) link_handle;

diff --git a/drivers/misc/ocxl/ocxl_internal.h b/drivers/misc/ocxl/ocxl_internal.h
index 5d421824afd921e1f679dfba3976516140bff879..a32f2151029f6584a6cf03b5512481d5f7846d95 100644 (file)
--- a/drivers/misc/ocxl/ocxl_internal.h
+++ b/drivers/misc/ocxl/ocxl_internal.h
@@ -77,6 +77,7 @@ struct ocxl_context {
        struct ocxl_xsl_error xsl_error;
        struct mutex irq_lock;
        struct idr irq_idr;
+       u16 tidr; // Thread ID used for P9 wait implementation
 };
 
 struct ocxl_process_element {

diff --git a/include/misc/ocxl.h b/include/misc/ocxl.h
index 51ccf76db293679387770f281b6e0479b7b14379..9ff6ddc28e221cdddb9d390d0543061f2ca1c1ae 100644 (file)
--- a/include/misc/ocxl.h
+++ b/include/misc/ocxl.h
@@ -188,6 +188,15 @@ extern int ocxl_link_add_pe(void *link_handle, int pasid, u32 pidr, u32 tidr,
                void (*xsl_err_cb)(void *data, u64 addr, u64 dsisr),
                void *xsl_err_data);
 
+/**
+ * Update values within a Process Element
+ *
+ * link_handle: the link handle associated with the process element
+ * pasid: the PASID for the AFU context
+ * tid: the new thread id for the process element
+ */
+extern int ocxl_link_update_pe(void *link_handle, int pasid, __u16 tid);
+
 /*
  * Remove a Process Element from the Shared Process Area for a link
  */

diff --git a/include/uapi/misc/ocxl.h b/include/uapi/misc/ocxl.h
index 0af83d80fb3ea42b7fe161e89073a6f7503bc6dd..561e6f0dfcb76b27013c7c82d47c32dd28778a61 100644 (file)
--- a/include/uapi/misc/ocxl.h
+++ b/include/uapi/misc/ocxl.h
@@ -48,6 +48,13 @@ struct ocxl_ioctl_metadata {
        __u64 reserved[13]; // Total of 16*u64
 };
 
+struct ocxl_ioctl_p9_wait {
+       __u16 thread_id; // The thread ID required to wake this thread
+       __u16 reserved1;
+       __u32 reserved2;
+       __u64 reserved3[3];
+};
+
 struct ocxl_ioctl_irq_fd {
        __u64 irq_offset;
        __s32 eventfd;
@@ -62,5 +69,6 @@ struct ocxl_ioctl_irq_fd {
 #define OCXL_IOCTL_IRQ_FREE    _IOW(OCXL_MAGIC, 0x12, __u64)
 #define OCXL_IOCTL_IRQ_SET_FD  _IOW(OCXL_MAGIC, 0x13, struct ocxl_ioctl_irq_fd)
 #define OCXL_IOCTL_GET_METADATA _IOR(OCXL_MAGIC, 0x14, struct ocxl_ioctl_metadata)
+#define OCXL_IOCTL_ENABLE_P9_WAIT      _IOR(OCXL_MAGIC, 0x15, struct ocxl_ioctl_p9_wait)
 
 #endif /* _UAPI_MISC_OCXL_H */